Tetra-substituted ureas



United States Patent *Ofiice 2,993,930 Patented July 25, 1961 2,993,930 TETRA-SUBSTITUTED UREAS Cecil C. Chappelow and Francis V. Morriss, Kansas City, Mo., assignors to Midwest Research Institute, Kansas City, Mo., a corporation of Missouri No Drawing. Filed Mar. '18, 1958, Ser. No. 722,122 3 Claims. (Cl. 260-553) The instant invention relates to tetra-substituted ureas, and more particularly, to tetra-substituted ureas having higher molecular weight substituents which have been found to have a unique combination of properties desirable for certain specific uses.

Although the compounds of the instant invention have a number of uses in various fields because of their wide liquid ranges (i.e. wide ranges between the melting points and boiling points thereof), these compounds are particularly useful in high temperature lubrication and their use in this particular respect will be emphasized in the instant specification. High temperature lubricants must remain liquid at the relatively high temperatures of use and these compounds must also remain liquid at substantially lower temperatures to which the compounds may be subjected when, for example, a high temperature device in which they are used is shut down or cooled off. Primarily, high temperature lubrication involves maintaining a liquid film of the lubricant between close running rigid surfaces at a high temperature to lubricate such surfaces. The instant tetra-substituted ureas have been found to be particularly useful for this purpose in that they have the requisite wide liquid ranges and they possess unique thermal stability.

Tetra-substituted ureas are known which have lower substituents thereon such as tetramethylurea. Also,

tetra-phenylurea is known, but such tetra-substituted ureas have relatively high melting points. in contrast, the tetrasubstitute-d ureas of the instant invention have low melting points and very high boiling points.

It is, therefore, an important object of the instant invention to provide novel tetra-substituted ureas.

It is a further object of the instant invention to provide novel tetra-substituted ureas for use as high tem perature lubricants and to provide a high temperature lubrication method involving the use of such tetra-substitnted ureas.

Other and further objects, features and advantages of the presentinvention will become apparent to those skilled in the art from the following detailed disclosurethereof.

Compounds which may be used in the practice of the instant invention include tetra-substituted ureas having the following formula:

R O R wherein at least one R is a C -C alkyl group, and the remaining Rs are each C --C saturated hydrocarbon groups.

As indicated from the formula of the foregoing paragraph, at least one of the Rs is a C C alkyl group. Preferably, at least two of the Rs are so defined. Such C -C alkyl groups include hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, including n hexyl, iso-hexyl, Z-ethylbutyl,

n-octyl, 2-ethylhexyl, n-decyl, lauryl, myristyl, cetyl, and stearyl. The remaining Rs may also fall in this group, and this is preferable so as to obtain tetrakis (higher alkyl) ureas. Also, these remaining Rs may include lower alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec.- butyl, tert.-butyl, isobutyl, n-amyl, etc.

Such remaining Rs may thus each be C -C alkyl groups. They may also be any other C -C saturated hydrocarbon group, which would include cycloaliphatic radicals such as cyclopentyl, methylcyclopentyl, ethylcyclopentyl, dimethylcyclopentyl, etc. cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, ethylcyclohexyl, etc. (wherein the alkyl substituents are preferably C -C alkyl groups).

The C C saturated hydrocarbon groups also include aromatic groups which contain no non-benzenoid unsaturation. The instant definition contemplates the exclusion only of nou-benzenoid unsaturation, such as olefinic or acetylenic unsaturation. For the purposes of the instant invention benzenoid unsaturation is equivalent to the saturated hydrocarbon bonds. Such aromatic groups include aryl and alkaryl radicals such as phenyl, tolyl, Xylyl, ethylphenyl, butylphenyl, hexylphenyl, phenylphenyl, nonylphenyl, etc.; alpha-naphthyl, betanaphthyl, methyl naphthyl, ethyl naphthyl, etc. (wherein the alkyl substituents on aryl groups are preferably C --C alkyl groups).

Another .group of compounds contemplated by the instant invention may be defined as tetra-substituted urea having the following formula:

wherein three As are each 0 -0 saturated hydrocarbon groups and the remaining A is a C -C alkyl group. In this group of compounds at least three As are C -C saturated hydrocarbon groups which include alkyl groups such as hexyl, heptyl, octyl, nonyl; decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, including n-heX-yl, iso-hexyl, Z-ethylbutyl, ethylhexyl, n-decyl, lauryl, myristyl, cetyl, and stearyl. Thethree As may also include C --C cyclic hydrocarbon groups such as cycloaliphatic radicals such as methylcyclopentyl ethylcyclopentyl, dimethylcyclopentyl, etc. cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, ethylcyclohexyl, etc. (where in the alkyl substituents are preferably C -'-C 5 alkyl groups). Also, the three As may include aryl and alkaryl radicals such as phenyl, tolyl, xylyl, ethylphenyl, butylphenyl, hexylphenyl, phenylphenyl, honylp'henyl, etc.; alphamaphthyl, beta-naphthyl, methyl naphthyl, ethyl naphthyl, etc. (wherein the alkyl substituents on aryl groups are preferably C -C alkyl groups). a

It will thus be seen that the definitions of the two groups of compounds overlap and we shall refer team as group I, which is tetra-substituted urea having the following formula:

and group II which is tetra-substituted urea having the following formula:

A compound such as n-butyltriphenylurea is included tions include within their scopes such compounds as tetran-hexylurea, tetrakis (Z-thylhexyl) urea, tetra-n-decylurea, tetra-n-octylurea.

The compounds of the invention include n-amyltriphenylurea, n-hexyltriphenylurea, n-octyltriphenylurea, n-decyltriphenylurea, n-octadecyltriphenylurea, etc., n-butyltritolylurea, etc., n-butyltrinaphthylurea, etc.; n-hexyltrimethylurea, n-hexyltriethylurea, noctyltrimethylurea, dihexyldimethylurea, dihexyldiethylurea, trihexylmethylurea, tetrahexylurea; n-butyltricyclohexylurea, t-butyltriphenylurea; 1,1- bis(p-biphenyl)-3-methy1-3-n-octadecylurea; 1,1-di-n-octadecyl-3-t-butyl-3-phenylurea; l-p-biphenyl-1-methyl-3-noctadecyl 3 phenylurea; 1-methyl- 1-n-octadecyl-3 p-biphenyl-3-o-tolylurea; m-terphenyl-tri-t-butylurea; etc.

Any of a number of synthetic methods may be employed to produce the compounds of the invention. These methods are indicated by equations hereinafter (wherein X represents either R or A hereinbefore defined).

Usually an inert hydrocarbon such as toluene or xylene is used as a solvent; and acid acceptors are used such as ZnO, MgO, pyridine, dimethylaniline and aqueous alkali.

Solvents such as benzene, chloroform, ether, and pyridine have been used; and an excess of the secondary amine or some tertiary amines have been used as acid acceptors.

This reaction is best carried out using excess tertiary amine as a solvent, employing reflux temperatures.

( 5) 2X NCOCl+2NaOH X NCONX +2NaCl+H O +CO This reaction which is exothermic may be carried out in aqueous media at reflux temperatures.

(7) ClCOOC H +2X NH Nickel is used here as a catalyst, using temperatures of 380400 C.

Example A T etra-n-hexylurea.Di-n-hexylamine (185.0 g., 1.0 mol.) and 500 ml. of toluene were placed in a two-liter flask fitted with a thermometer, stirrer, condenser, and gas inlet tube. Phosgene (24.7 g., 0.25 mol.) was bubbled into the stirred solution while the temperature was held at 40 C. by applying external cooling. The addition was complete in 1 hour. The reaction mixture was held at 110 C. for 8 hours with stirring. The toluene was removed from the reaction mixture by distillation (final pot temperature 200 C.) leaving a residue of solid and oil. The residue was partitioned between 300 ml. of ether and 300 ml. of 20 percent KOH solution. The ether layer was washed with 20 percent K CO solution and dried over anhydrous Na SO The ether was distilled off leaving an oil.

Two subsequent vacuum distillationsyielded the prod uct, a straw colored liquid, B.P. 156158 C./0.035 mm., M.P. 20 to 19 C., 11. 1.4559, df 0.8641. The molar refraction was 124.73 obsd.: 125.50 calc. The yield was 45 .0 g. or 45.5 percent of theory.

' dropwise to the stirred reaction mixture.

4 Example B ml. of ether and 300 ml. of 20 percent KOH solution.

The ether layer was dried over anhydrous Na SO and distilled oif leaving a dark oily residue.

Two vacuum distillations gave 40.0 g. of product, a pale yellow oil, B.P. 176-178 C./0.035 mm. solidification point 40 0., n 1.4631, d 0.8716. The molar refraction was 160.84 obsd.; 162.54 calc. The yield was 40.0 percent.

Example C 1,3 a'i n hexadecyl 1,3 dimethylurea.N methyl-n-hexadecylamine (87.0 g., 0.34 mol.) and 500 ml. of pyridine were placed in a one-liter flask fitted with a thermometer, stirrer, reflux condenser, and a gas inlet tube. Phosgene (17.0 g., 0.17 mol.) was bubbled into the reaction mixture with stirring. During the one hour addition period, the temperature was maintained below 40 C. by applying external cooling. Then, the reaction mixture was held at 120 C. for 3 hours with stirring. The pyridine was stripped from the reaction mixture by an atmospheric distillation. The oily residue was partitioned between 300 ml. of ether and 300 ml. of 10 percent KOH solution. The ether layer was dried over anhydrous Na SO and the ether distilled ofl leaving a dark oily residue.

The product, obtained after two vacuum distillations, was a yellow oil, B.P. 254-256 C./0.125 mm. 11 1.4630, d 0.8234 (super cooled). The molar refraction was 179.31 obsd.; 171.80 calc. On standing, the product solidified, becoming a light tan solid, M.P. 36- 38 C. The yield was 30.0 g. which is equivalent to 33.0 percent of the theoretical.

Example D 1,] diphenyl 3 n hexadecyl 3 methylurea.-Di phenylcarbamoyl chloride (46.4 g., 0.20 mol.) and 200 m1. of pyridine were placed in a one-liter flask equipped with a thermometer, stirrer, reflux condenser, and additional funnel. A solution of N-methyl-n-hexadecylamine (51.0 g., 0.20 mol.) in 200 ml. of pyridine was added The addition of the amine caused a slight temperature rise. After the addition was complete, the reaction mixture was held at 120 C. for 6 hours with stirring. The pyridine was distilled OE and the residue was shaken with 300 ml.

" of ether and 300 ml. of 10 percent KOH solution. The

Tetra-n-octflarem-Di-n-octylamine (96.6 g., 0.40-

mol.) and 500 ml. of toluene were placed in a one-liter flask equipped with a thermometer, stirrer, reflux condenser, and gas inlet tube. Phosgene (9.9 g., 0.10 mol.) was bubbled into the solution with stirring. During the addition the temperature was kept below 35 C. by applying external cooling. After the addition was complete, the temperature was gradually increased to 110 C. and held there for 16 hours with stirring. The reaction mixture was cooled to C. and the di-n-octylamine hydrochloride (57 g., 0.20 mol.) was filtered otf. The toluene was removed from the filtrate by distillation and the residue was partitioned between 300 m1. of ether and 300 ml. of percent KOH solution. The ether layer was dried over anhydrous NaSO and the ether distilled off, leaving an oily residue which was subjected to a vacuum distillation.

The product was a yellow colored oil, 13:1. 210-2l2 C./0.11 mm., 3.5-4.5 C., n 1.4598, 41 0.8607. The molar refraction was 161.90 obsd.; 162.54 calc. A total of 35.0 g. of product was obtained which represents a 70.0 percent yield.

Example F Tetra-n-decylurea.--Di-n-decylamine (42.8 g., 0.48 mol.) and 500 ml. of toluene were placed in a one-liter flask equipped with a thermometer, stirrer, reflux condenser, and gas inlet tube. Phosgene (23.8 g., 0.24 mol.) was bubbled into the stirred reaction mixture while the temperature was held below 35 C. by applying external cooling. After the addition was complete, the reaction mixture Was slowly heated to 110 C. and held there for 16 hours with stirring. The toluene was distilled 011. The residue was refluxed with 200 ml. of 10 percent KOH solution for 1.5 hours with stirring. This reaction mixture was extracted with 300 ml. of ether. The ether layer was dried over anhydrous Na SO The ether was distilled 011 and the residue vacuum distilled.

The product was obtained after two distillations. It was a yellow oil, B.P. 246-247 C./0.08 mm., n 1.4622, 613 0.8582. The molar refraction was 199.00 obsd.; 194.33 calc. By cooling, the product solidified to a pale yellow solid, M.P. 25.5 -27.0 C. The yield was 70.0 g. equivalent to 47.0 percent of the theoretical.

Example G n Butyltrz'phenylurea.--Diphenylcarbamoyl chloride 57.9, 0.25 mol.), N-n-butylaniline (74.6 g., 0.50 mol.), and 400 m1. of toluene were placed in a one-liter flask fitted with a thermometer, stirrer, and reflux condenser. The reaction mixture was held at 100 C. for 16 hours with stirring. The reaction mixture was cooled to 10 C. and the N-n-butyl aniline hydrochloride (36.0 g., 0.205 mol.) was filtered off. The toluene was removed from the filtrate by distillation and the resdiue was partitioned between 300 ml. of ether and 300 ml. of 10 percent KOH. The ether layer was dried over anhydrous Na SQ, and the ether distilled off. The residue was vacuum distilled through a Claisen head.

The product was a very viscous yellow oil, B.P. 191- 196 C./0.055 mm., 11,, 1.5939, d 1.0796, solidification point 15 C. The molar refraction was 108.26 obsd.; 106.07 calc. A total of 55 .g. of product was obtained which represents a 64.0 percent yield,

The compounds of the instant invention have been found to have low melting points and very high boiling points or volatilization temperatures. Typical melting points and volatilization temperatures are set forth in the following table:

1 solidification pt.; no true melting point could be determined.

The foregoing results indicate clearly that the melting point is low for each of these compounds and the volatilization temperature is very high, so as to give a wide liquid range for the compounds. In contrast, tetraphenylurea has a melting point of 182184.5 C.; methyltriphenylurea has a melting point of 106-107.5 C.; and benzyltriphenylurea has a melting point of 108-110.5 C.

Each of the compounds of the invention has also been found to have good thermal stability and these compounds afford the industrial advantage that they can be prepared by simple and relatively inexpensive procedures.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

We claim as our invention:

1. Tetra-substituted urea of the formula:

wherein three As are selected from the group consisting of C -C phenyl, alkylphenyl, phenylphenyl, naphthyl and alkylnaphthyl and the remaining A is selected from the group consisting of C C alkyl.

2. 1,1-diphenyl-3-n-hexadecyl-3-methylurea.

3. n-Butyltriphenylurea.

References Cited in the file of this patent UNITED STATES PATENTS 1,437,027 Tanberg Nov. 28, 1922 1,477,087 Tanberg Dec. 11, 1923 2,668,758 Roos et a1. Feb. 9, 1954 2,706,534 Hunter Apr. 19, 1955 2,768,971 Jones Oct. 30, 1956 2,817,684 Bortnick Dec. 24, 1957 2,839,159 Peters et a1 June 17, 1958 OTHER REFERENCES Dains et al.: J. Am. Chem. Soc., vol. 38, pages 131- (1916).

Gizycki: Z Anal. Chem., vol. 44; pp. 109-11 (1955). 

1. TETRA-SUBSTITUTED UREA OF THE FORMULA: 